Talk given by Ole Jensen of the Donders Institute at University Nijmegen, Netherlands. Given to the Redwood Center for Theoretical Neuroscience at UC Berkeley on June 24, 2009.
The working brain is composed of multiple networks which must be flexibly engaged and disengaged. How is this functional architecture shaped? Recent electrophysiological studies strongly suggest that networks not important for a given task are disengaged by an increase in oscillatory alpha activity (8-13 Hz). We propose that active processing, reflected by neuronal synchronization in the gamma band (30-150 Hz), is directed to task-relevant networks by blocking off task-irrelevant regions by means of alpha activity. The study of these principles require tools in which functional connectivity is investigated by means of cross-frequency analysis. Insight from our investigations points to a new framework for understanding neuronal processing in which the disengagement of irrelevant networks is a necessity for shaping the functional connectivity in order to ensure optimal task performance.
• Mazaheri, A, and Jensen, O. (2008) Amplitude modulations of brain oscillations generate slow evoked responses. Journal of Neuroscience 28:7781-7787.
• Osipova, D., Hermes, D. and Jensen, O. (2008) Gamma power is phase-locked to posterior alpha activity. PLoS ONE 3(12): e3990
• Jensen, O. and L. L. Colgin (2007) Cross-frequency coupling between neuronal oscillations. Trends in Cognitive Sciences 11:267-269.
• Jensen, O., Kaiser, J. and J.P. Lachaux (2007) Human gamma oscillations associated with attention and memory. Trends in Neurosciences 30:317-324